src: Introduce socket matching

For now it can only match sockets with IP(V6)_TRANSPARENT socket option
set. Example:

 table inet sockin {
	chain sockchain {
		type filter hook prerouting priority -150; policy accept;
		socket transparent 1 mark set 0x00000001 nftrace set 1 counter packets 9 bytes 504 accept

	}
 }

Signed-off-by: Máté Eckl <ecklm94@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/socket.h b/include/socket.h
new file mode 100644
index 00000000..a2ae9f10
--- /dev/null
+++ b/include/socket.h
@@ -0,0 +1,24 @@
+#ifndef NFTABLES_SOCKET_H
+#define NFTABLES_SOCKET_H
+
+//#include <parser.h>
+
+/**
+ * struct rt_template - template for routing expressions
+ *
+ * @token:	parser token for the expression
+ * @dtype:	data type of the expression
+ * @len:	length of the expression
+ * @byteorder:	byteorder
+ */
+struct socket_template {
+	const char		*token;
+	const struct datatype	*dtype;
+	unsigned int		len;
+	enum byteorder		byteorder;
+};
+
+extern struct expr *socket_expr_alloc(const struct location *loc,
+				    enum nft_socket_keys key);
+
+#endif /* NFTABLES_SOCKET_H */